Using FFT/Room analysis software

[ethan_c]

Two part question:

1. What is a good FFT/Room analysis program to check out my room?

2. How does one use this? Do you send a test tone through your system and capture it? What should the FFT read? Should it be flat and if so at what db/level?

I can't seem to find any actual informative info on this anywhere... ie: how to read or work the software...

Ethan

[Ethan Winer]

Ethan,

It had to happen eventually. Say, are you my long lost brother?

> What is a good FFT/Room analysis program to check out my room? <

I use the ETF software:

www.acoustisoft.com

> How does one use this? Do you send a test tone through your system and capture it? What should the FFT read? Should it be flat and if so at what db/level? <

An entire book could be written to explain this. There are several articles on the Articles page of my company's site that explain what ETF does, with many examples of the type of data it can report. Start there, then feel free to post any follow-up questions. You can also download a semi-functional demo from the ETF site I linked above.

In the mean time, the key features of ETF are:

* ETF can display low frequency response to a resolution of 0.7 Hz, which is needed to see the true picture in small rooms.

* ETF can display waterfall plots showing decay time at individual mode frequencies. Escessive modal decay (ringing) is at least as big a problem as a skewed response, and is a better way to assess the before / after improvement from adding bass traps and other acoustic treatment.

* ETF can show individual reflections and how much later they arrive.

--Ethan